Shortly after midnight on a warm Saturday in September, Dwayne Crumholt pulled his pickup truck down a quiet country road in Central toward his cousin’s trailer, just a few hundred feet away from his own.

Minutes earlier, Crumholt and other revelers at an LSU game party heard the crack of gunfire. In the driveway, Crumholt found his cousin, Rodney Chemin, dead, a .45-caliber pistol near his hand. Next to him were the lifeless bodies of three brothers, all among Crumholt’s closest friends.

The horrific events marked a stark turn in a night that started out as boisterous — a party among friends capped with the shooting of Joseph Allen, 57; Perry Allen, 55; and Mark Allen, 51.

That Saturday was clear and warm. A few dozen people gathered at Crumholt’s trailer to watch LSU play Mississippi State. A big pot of pastalaya cooked outside, and music blared from speakers as the crowd drank beer and cheered the Tigers on to their first victory of the year, according to witness accounts included in an East Baton Rouge Sheriff’s Office report.

As the party carried on into the night, a heated argument broke out over karaoke music playing outside. A switch to singing rock ’n’ roll and rap songs instead of country tunes sparked the fight, which turned physical with pushing and shoving inside the trailer. Later, another, more violent confrontation took place.

At some point after the second fight came the burst of gunfire from near Chemin’s trailer just down the road. A few seconds later, a single shot followed. When sheriff’s deputies arrived, they found all three brothers lying face down on the driveway. Nearby, Chemin, with a black nylon holster over his shoulder, was also dead from a self-inflicted gunshot to the head, the coroner ruled.

No one else witnessed the shootings, and just what happened in those final moments remains elusive for the men’s families and investigators alike. The sheriff’s report, recently released to The Advocate, offers new details and insights into what led up to those fatal shots. But in the end, it doesn’t resolve the crucial mystery of why Chemin opened fire. Did he shoot in cold blood at three men heading to his house to make amends, as their relatives contend? Or was he afraid of the brothers, as one witness suggested to detectives?

Some haziness around the events isn’t surprising as the beer-fueled party carried on toward midnight. The man whose karaoke selections touched off the initial disagreement told detectives everyone at the party was drinking heavily, the report says. Crumholt told deputies, who arrived shortly after the shooting, that most of his guests were drinking but nobody appeared to be “very drunk” to him. The report noted that Crumholt appeared “very intoxicated” to an investigator.

Crumholt, who the day after the Sept. 13 shootings described all four as “great men,” did not return messages seeking comment.

Partygoers told detectives the confrontation over the music — which a few witnesses blamed on one or more of the Allens, while in one recounting was provoked by Chemin — left those involved angry. Crumholt took Joseph Allen, whom he described to detectives as his best friend, for a ride in a golf cart to cool off.

Meanwhile, five witnesses said they heard Chemin, 60, threatening to get a gun or shoot the Allens, the Sheriff’s Office report indicates. One witness said he overheard Chemin tell Perry and Mark Allen, “If you come down there and mess with me, I’ll blow your head off.”

According to three of those at the party, those threats touched off a second altercation between Chemin and the remaining two Allen brothers. Angered by the threats, witnesses say Perry Allen headed back inside, confronted Chemin and touched off a second scuffle, during which Mark Allen’s elbow was pushed through a wall, leaving him bloodied. By some witness accounts, Chemin was also hit in the head.

Shortly after the second fight, Chemin left the party, riding his motorcycle to his trailer just a short way down the road.

Arriving back at the party just after Chemin left, Crumholt and Joseph Allen found his injured brother. Two witnesses recounted him saying he would “whip” Chemin, although summaries of interviews of other partygoers don’t note that proclamation.

What happened next is less clear.

A few witnesses didn’t notice the Allen brothers leave the party and in some accounts they appeared to leave separately. Two witnesses told detectives Joseph Allen drove back on the golf cart, wrecked it against a tree and returned to the party before heading back toward Chemin’s home.

One partygoer recounts calling Chemin at 12:13 a.m., warning him the brothers “were on the way to his house to fight him,” the report says.

That same witness later told detectives Chemin replied, “I don’t know what I’m going to do” before hanging up. Five minutes later, Chemin called back, saying, “Man, I’m scared s***less. I don’t know what I’m gonna do.”

Then gunfire was heard. Single shots to the chest killed both Joseph and Mark Allen, an autopsy later revealed. Perry Allen, shot once in the chest, was shot a second time through the back. Then Chemin took his own life, investigators concluded.

Exactly what happened just before and during those deadly moments will almost certainly never be known. The Sheriff’s Office officially ended its investigation Nov. 11 — closed, the report noted, by “exceptional clearance because the only known offender is deceased.”

No jury will ever weigh the evidence in the case, something that bothers the Allen brothers’ family. A day in court could have provided the family a degree of closure and a chance to face their killer, said Gregory Allen, a younger brother of the three slain men.

“There’s no one to confront,” said Vera Faubion, the Allens’ 75-year-old mother, as she sat with three of her four surviving children on the patio outside Mark Allen’s well-kept trailer in Denham Springs. “You can’t confront the man who did it. There’s no one to be held accountable.”

For the Allen family, the grief hasn’t subsided in the months since the three brothers — a tight-knit group who spent many weekends together — were killed.

“I live in a different world,” said their sister, Patricia Allen. “One day I had five brothers and the next day I had two. I wake up every day crying. It’s hard to get through the day.”

“It’s not over, and it’ll never be over,” said Faubion. “Someone snatched my sons from me in cold blood.”

If Chemin had lived, East Baton Rouge Parish District Attorney Hillar Moore III said, a grand jury would’ve almost certainly presented a range of charges, from second-degree murder to manslaughter. Prosecutors would’ve also presented the possibility of self-defense, he said.

“While there are witnesses to the actions that preceded the shooting, there are none at the shooting,” Moore said. It’s “hard to make a decision without actual witnesses.”

An obituary in The Advocate for Chemin, a welder and Baton Rouge native, said he “loved to fish, hunt and play volleyball.”

Reached by phone, Carl Chemin, Rodney Chemin’s brother, said he didn’t want to talk to a reporter about what happened, but added, “They come to kill him. That’s all that’s got to be said about it.”

But the Allens reject that contention. Even if tempers flared at the party, Patricia Allen said she can’t imagine her brothers went back to Chemin’s trailer to attack him. Unarmed, with nothing but wallets and a bit of loose change in their pockets, Patricia Allen said her brothers went back to resolve the dispute and “get it straight.”

“They were the type of people that would try to make amends,” she said.